“The wheel was invented by the ancient Sumerians. They lived in the land between the Tigris and the Euphrates Rivers in the Middle East. Much, much later this land became part of the country we call Iraq. The Sumerians were the first people to develop a written language. Extensive studies of their writings have led archaeologists and historians to also credit them with the invention of the wheel.
The concept of the wheel actually grew out of a mechanical device that the Sumerians had invented shortly after 3500 B.C.—the potter’s wheel. No other civilization of their time had one. This was a heavy flat disk made of hardened clay. It was spun horizontally on an axis to allow the potter to form evenly shaped jars and bowls from wet clay. The Sumerians didn’t, however, simply turn this clay-splattered wheel on its end and hook it to a wagon to make a wheel. Instead, the concept of the wheel went through many stages of development before it became a practical method for moving heavy objects from one location to another.” Source